When a dangerous goods transport vehicle is temporarily parked during transit (such as at an expressway service area or authorized parking lot), what rule applies to the crew (driver and escort)?

1. The crew must not leave the vehicle unattended simultaneously; at least one person must remain on duty to guard the vehicle or keep it within direct visual line of sight
2. Both crew members must immediately leave the parking lot and take a taxi to the city center for entertainment
3. The driver must hand the ignition keys to an unauthorized stranger in the parking lot
4. The escort must sleep in an off-site hotel with their mobile phone switched off